EP3408108A1

EP3408108A1 - Method for producing a printed decorative panel

Info

Publication number: EP3408108A1
Application number: EP17701147.5A
Authority: EP
Inventors: Carsten Buhlmann
Original assignee: Surface Technologies GmbH and Co KG
Current assignee: Surface Technologies GmbH and Co KG
Priority date: 2016-01-25
Filing date: 2017-01-24
Publication date: 2018-12-05
Anticipated expiration: 2037-01-24
Also published as: WO2017129566A1; CN108698435B; EP3196046A1; CN108698435A; US20190023061A1; US10814669B2; ES2848183T3; EP3408108B1

Abstract

The invention relates to a method for producing a printed panel, comprising the following steps: a) providing a flat carrier (12); b) optionally applying a resin layer (18) to the flat carrier (12); c) optionally applying a paper layer or nonwoven layer (22) to the flat carrier (12); d) optionally calendering the produced layer structure, in particular at a temperature between ≥ 40 °C and ≤ 250 °C, and e) optionally applying a printing substrate (26) to the flat carrier (12); characterized in that the method has the following further steps: f) printing an application amount of radiation-curing printing ink (30) onto the carrier (12), and g) curing the previously applied printing ink (30) by treating the printing ink (30) with radiation, wherein h) at least one parameter of radiation used in step g) is adapted to an application amount of radiation-curing printing ink (30), wherein step h) is based on an application amount of the radiation-curing printing ink (30) determined by a sensor during the printing process, wherein at least one parameter of radiation used in step g) is adapted during the printing on the carrier (12) according to step f).

Description

Method for producing a printed decorative panel

The present invention relates to a method for producing a printed matter

Dekorpaneels. In particular, the present invention relates to a method of making a printed decorative panel having radiation-curable ink which enables improved curing of the radiation-curable ink.

Decorative panels, for example for interior design, are known per se. So far, such decorative panels are often produced as laminates, in which on a carrier plate with a desired decor pre-printed decorative paper is applied, which in turn is then applied a so-called overlay. Furthermore, direct printing methods are known in which the carrier plate itself or a non-printed paper applied to the carrier plate is printed.

As further treatment steps, it may be provided, for example, to apply wear or cover layers above the decorative layer to protect the applied decorative layer. A wearing and / or covering layer in the sense of the invention is a layer applied as an outer finish, which in particular protects the decorative layer from wear or damage by dirt, moisture or mechanical influences, such as, for example, abrasion.

It is often provided that in such wear or cover layers one with the

Decor matching surface structuring is introduced. Under one with the

Decor matching surface texturing is to be understood that the surface CD 41495: UAM of the decorative panel has a haptic perceptible structure, which corresponds in shape and pattern of the applied decor, so as to obtain as faithful as possible reproduction of a natural material also in terms of haptics. A problem that can occur when printing directly on decorative panels, is that the printed ink or the decor often has to be completely dried before further treatment steps, so as to ensure a high quality of the decor. This can possibly reduce the production speed. Such a problem can equally apply to printing a paper applied to a carrier plate as well as to the direct printing of the carrier plate.

EP 1 918 108 A1 deals in particular with an ink composition and an inkjet printing process, in particular radiation-curable compositions being described. The substrate to be printed is in particular paper, glass, plastic, films, metal and printed circuit boards. It is further generally described that the conditions used for the irradiation are selected based on the predetermined amount and thickness of the ink adhered to the substrate.

US 2007/0040885 A1 describes a printing method and an arrangement for printing, in particular, a paper using radiation-curing ink. In this case, it is provided in particular that the ink has curing initiators which are active for radiation of different wavelengths, so that first partial curing and then final curing can take place. It is further described that a control unit is provided which adjusts the radiation energy of a radiation unit depending on the type of ink and the amount of ink applied to a substrate. In this case, the amount of ink is determined based on an image to be printed, that is based on predetermined data. US 2012/0176436 AI is concerned with a printing process such as for printing on paper. It should in particular be provided that ink is applied to the substrate to be printed and is irradiated from the opposite side to achieve a curing of the ink. It is described that the amount of radiation or the irradiation time is adjusted based on the amount of the ink applied to the substrate to be printed. This is done on the basis of predetermined print data.

Taking this into account, it is the object of the present invention to provide a method for producing a decorative panel which is able to overcome at least in part a problem known from the prior art. In particular, it is the object of the present invention to provide a method for producing a decorative panel, which allows an improved application of a decoration by means of a printing process. This object is further achieved by a method according to claim 1. Preferred embodiments of the invention are given in the dependent claims and the further description and the figures, wherein the other features described individually or in a Any combination may form part of the invention, as far as the opposite does not explicitly result from the context.

A process for producing a printed panel is proposed, comprising the method steps:

a) providing a plate-shaped carrier; b) optionally applying a resin layer to the plate-shaped carrier; c) optionally applying a paper or non-woven layer to the plate-shaped carrier; - zi _¬

el) optionally calendering the resulting layer structure, in particular at a temperature between> 40 ° and <250 ° C,

e) optionally applying a printing substrate to the plate-shaped carrier, the method comprising the further method steps:

f) printing the carrier with an application amount of radiation-curable ink and; g) curing the previously applied ink by treating the ink with radiation, wherein

h) at least one parameter of radiation used in step g) is adapted to the application amount of radiation-curable ink, wherein

Method step h) is based on an application quantity of the radiation-curable printing ink determined by at least one sensor during the printing process, wherein at least one parameter of radiation used in method step g) is adapted during printing of the carrier according to method step f). Surprisingly, it has been shown that an improved application of the decoration on a carrier plate or on a paper arranged on the carrier plate can be effected by the method described above.

For the purposes of the invention, the term decorative panel means wall, ceiling, door or floor panels which have a decor applied to a carrier plate. Decorative panels are used in a variety of ways, both in the field of interior design of rooms, as well as the decorative cladding of buildings, for example in exhibition construction. One of the most common uses of decorative panels is their use as floor coverings. The decorative panels often have a decor that is intended to recreate a natural material.

Examples of such simulated natural materials are wood species such as maple, oak, birch, cherry, ash, walnut, chestnut, wenge or even exotic woods such as pangas. Panga, mahogany, bamboo and bubinga. In addition, many natural materials such as stone surfaces or ceramic surfaces are modeled.

For the purposes of the invention, the term "direct printing" refers to the application of a decoration directly to the support of a panel or to a non-printed fibrous material layer applied to the support. Contrary to conventional methods in which a decorative layer previously printed with a desired décor is applied to a support, direct printing of the decoration is effected directly in the course of surface coating or panel production. In this case, different printing techniques can be used, which can work with printing inks, such as in particular digital printing techniques, such as inkjet or laser printing method.

For the purposes of the invention, by the term fiber materials, materials such as e.g. Paper and nonwovens based on vegetable, animal, mineral or even artificial fibers to understand, as well as cardboard. Examples of fibrous materials made of vegetable fibers, in addition to papers and fleeces of pulp fibers, plates of biomass such as straw, maize straw, bamboo, foliage, algae extracts, hemp, cotton or Olpalmenfasern. Examples of animal fiber materials are keratin-based materials such as e.g. Wool or horsehair. Examples of mineral fiber materials are mineral wool or glass wool.

In the method described above, according to method step a), provision is first made of a plate-shaped carrier. The carrier provided according to method step a) can be designed in a manner known per se for the production of decorative panels. Depending on the desired area of use of the decorative panels, the carrier may be made of different materials. In particular, the material of the carrier can be selected depending on the field of application. For example, the carrier can consist of or have a wood-based material, provided that the decorative panel is not exposed to excessive moisture or weather conditions. If, on the other hand, the panel is to be used, for example, in damp rooms or outdoors, the support may for example consist of or comprise a plastic. Wood materials in the context of the invention are in addition to solid wood materials and materials such as cross-laminated timber, glued laminated timber, hardwood plywood, plywood, laminated veneer lumber, Funierstreifenholz and bending plywood. In addition, under wood materials in the context of the invention, wood chip materials such as chipboard, extruded, coarse chipboard (Oriented Structural Board, OSB) and chipboard wood and wood fiber materials such as Holzfaserdämmplatten (HFD), medium-hard and hard fiberboard (MB, HFH), and in particular medium density Fiber boards (MDF) and high density fiberboard (HDF). Also modern wood materials such as wood polymer materials (WPC), sandwich panels of a lightweight core material such as foam, rigid foam or paper honeycomb and a wood layer applied thereto, as well as mineral, eg cement, bonded wood chipboard form wood materials in the context of the invention. Cork also represents a wood material in the context of the invention.

Plastics which can be used in the production of corresponding panels are, for example, thermoplastics, such as polyvinyl chloride (PVC), polyolefins (for example polyethylene (PE), polypropylene (PP), polyamides (PA), polyurethanes (PU), polystyrene (PS) Acrylonitrile-butadiene-styrene (ABS), polymethyl methacrylate (PMMA), polycarbonate (PC), polyethylene terephthalate (PET), polyetheretherketone (PEEK), or mixtures or copolymers thereof, for example, a copolymer of polyethylene and polypropylene, for example in a ratio Further, by way of example, a wood and a polymer which may be present in a ratio of 40/60 to 70/30, for example 50/50, may be suitable. As the polymer components, polypropylene, polyethylene or a copolymer of, for example, can be used the two aforementioned Materials may be used, wherein furthermore wood flour can be used as wood component. The plastics may in principle contain conventional fillers, for example calcium carbonate (chalk), aluminum oxide, silica gel, quartz flour, wood flour, talc.

In the case of plastic-based panels, for example based on polyvinyl chloride, as well as on WPC-based panels, for example based on polypropylene and / or polyethylene, mineral fillers may be advantageous. Talc or talc or else calcium carbonate (chalk), aluminum oxide, silica gel, quartz flour, wood flour, gypsum are particularly suitable here. For example, chalk may be provided. The proportion of mineral fillers, such as talc, may be in a range from> 30% by weight to <80% by weight, for example from> 45% by weight to <70% by weight. By the fillers, in particular by the chalk, the slip of the wearer can be improved. For example, by using talc, it may be possible to provide improved heat resistance and moisture resistance. For example, talc can be used as a filler in a WPC material, such as a wood component, such as wood fibers together with a plastic, as described above, or even to a pure plastic. Also, the fillers may be colored in a known manner. For example, a mixture of talc and polypropylene may be present in which talc is present in the abovementioned amount range, for example at 60% by weight. In particular, it may be provided that the plate material has a flame retardant.

Such a carrier is provided in a method described above with a decor. For this purpose, the carrier can be printed using radiation-curable ink, as described in detail below. Printing of the carrier can be realized directly on the carrier within the meaning of the invention or likewise encompassed by the present invention on a fibrous web or another suitable printing substrate of the carrier and thus indirectly on the carrier. Thus, under a printing of the carrier as well as with the application of a layer on the carrier or the application of a material to the carrier understood the immediate printing of the carrier or the application of a layer directly on the relationship meadow the application of a material to the carrier as well indirectly to a layer on the support.

Insofar as the printing is to take place on a fibrous web or on a paper or nonwoven layer, it can be provided that first the paper or nonwoven layer is applied to the carrier and printed directly or provided with a printing substrate and then printed.

In the case of application of the paper or nonwoven layer, a resin layer can preferably be applied to the plate-shaped support following the process step a) according to process step b), which can serve as an adhesive for fixing the paper or nonwoven layer. In this case, a resin composition known per se can be used in this process step. Furthermore, this method step can again find application by the use of applicator rolls.

For applying the resin layer in step b), it may be preferable to apply a resin composition having as a resin component at least one compound selected from the group consisting of melamine resin, formaldehyde resin, urea resin, phenolic resin, epoxy resin, unsaturated polyester resin, diallyl phthalate or mixtures thereof , In this case, the resin composition, for example, in an application amount between> 5 g / m ² and <50 g / m ² , preferably> 10 g / m ² and <40 g / m ² be applied. Particularly preferably, the application amount of the resin composition is chosen so that the paper or nonwoven applied in the subsequent step c) is not completely impregnated with the resin composition. Preferably, penetration of the resin layer before printing can be prevented by selecting the kind and amount of the applied resin layer. For this purpose, it may, for example, also be provided that the resin composition in step b) is applied with a kinematic viscosity which corresponds to a flow time of between> 10 s and <40 s from a standard flow cup (measured in accordance with DIN 53211). Subsequently, according to method step c), the paper or nonwoven layer can be applied to the plate-shaped carrier or to the resin layer. It may be provided that in step c) a paper or non-woven with a grammage between> 30 g / m ² and <80 g / m ² , preferably between> 40 g / m ² and <70 g / m ² on the plate-shaped carrier is applied. The application of the paper or of the nonwoven fabric can be realized, for example, by means of suitable feed rollers which guide the paper or nonwoven such that it is arranged on the carrier.

After application of the paper or nonwoven layer, according to method step d), calendering of the resulting layer structure can follow, in particular at a temperature between> 40 ° and <250 ° C. This step can be carried out in a basically known manner by the method of layer construction by a calender having calender rolls, which treats the layer structure with pressure and / or heat. During calendering, the resin layer may remain uncured or, preferably, partially or fully cured.

In the event that the method thus has the application of a paper or nonwoven and thus approximately the method steps b) to d), the printing of the carrier according to method step e) is carried out following the calendering according to method step c) or im Following the application of a printing substrate, in particular on the calendered layer structure, as described below. The following statements apply equally when dispensing with a paper or nonwoven layer and the printing substrate is applied directly to the carrier.

Such a printing substrate comprises, for example, a resin system, for example comprising a melamine resin. For example, to form the printing substrate, successive two-time application of each resin composition to form two resinous layers can be carried out using the method steps: forming a first resinous layer using a resin composition having a mixture of melamine resin and urea resin; and forming a second resinous layer using a resin composition having a content of melamine resin in the resin content which is in a range of> 95% by weight, especially> 99% by weight. Basically, the printing substrate can be made one or more layers, wherein each of the layers have a resin content or may consist thereof. In this case, in each layer, the resin may comprise or consist of urea resin or melamine resin so that the proportion of urea resin in the resin content may be, for example, from> 0 wt% to <100, the remainder being, for example, melamine resin and / or wherein the proportion of melamine resin in the resin content, for example, from> 0 wt to <100 may make up, the remainder may be formed for example by urea resin.

In principle, the particular resin composition may have, for example, a resin content of between> 15% by weight and <95% by weight, preferably between> 20% by weight and <90% by weight, more preferably between> 25% by weight and < 65 wt. Furthermore, the first resinous layer can be applied with a mixture comprising only melamine resin and urea resin in the resin portion. In this case, melamine resin can be present in the resin fraction, for example, in a proportion which is in a range from> 55% by weight to <90% by weight, for example> 60% by weight to <80% by weight, approximately 70% by weight, wherein the remaining portion of the resin portion may each be formed of urea resin. For example, the first resinous layer according to method step el) is applied with an amount which is smaller than the amount of the applied second resinous layer according to method step e2). For example, the first resinous layer in step el) can be in an amount in a range of> 10 g / m ² to <25g / m ^2, for example in a range of> 15 g / m ² to <20 g / m ^2, are applied , and may be the second resinous layer in process step e2) with an amount in a range of> 20 g / m ² to <40 g / m ² , for example in a range of> 25 g / m ² to <35 g / m ² , are applied. In this case, it may be preferred that in process step e) a resin composition is applied which comprises as solid at least one compound from the group consisting of titanium dioxide, barium sulfate, barium oxide, barium chromate, zirconium (IV) oxide, silicon dioxide, aluminum hydroxide, aluminum oxide, iron oxide, iron ( III) hexacyanoferrate, chromium oxide, cadmium oxide, cadmium sulfide, cadmium selenite, cobalt oxide, cobalt phosphate, cobalt aluminate, vanadium oxide, bismuth vanadium oxide, tin oxide, copper oxide, copper sulfate, copper carbonate, lead antimonate, lead chromate, lead oxide, lead carbonate, calcium carbonate, calcium sulfate, calcium aluminate sulfate, zinc oxide, zinc sulfide, arsenic sulfide, Mercury sulfide, carbon black, graphite, cellulose fibers or mixtures thereof. Through the use of such solids, it is possible in particular to provide a colored printing substrate whose coloration has a property which supports the decor pressure. Thus, for example, in a decorative design, which is to represent a dark wood, a printing substrate with a brown or brownish ground tone are applied, while in a decor design, which is a light wood or a light stone represent a print substrate to be applied with a yellow or white tone. The use of cellulose fibers in the resin composition applied to the plate-shaped carrier in particular has the advantageous effect that any irregularities on the carrier plate surface, on which the resin composition is applied, no longer penetrate the surface to be printed later, resulting in a significant improvement of the printed image leads. Such irregularities may be, for example, grinding grooves of loops of the carrier plates or impressions by conveying means, such as conveyor belts, etc. When using cellulose fibers, these preferably have a particle size in the range between> 10μιη and <100μιη, in particular between> 25μιη and <90μιη. The proportion of the cellulose fiber in the solid contained in the resin composition may, for example, in a range between> 0 wt .-% and <100 wt .-., Preferably between> 40 wt .-% and <100 wt .-%, in particular between> 60% by weight and <100% by weight. lie. In this case, the preferred proportion of solids in the resin composition with the use of cellulose fibers at the lower end of the wt% range, preferably between 0.5 and 3.5 parts by weight, in particular between 1.0 wt. and 2.5% by weight, whereas the preferred proportion of solids in the resin composition in the other solids which are listed as suitable, for example, is preferably between> 5% by weight and <85% by weight, preferably between> 10% by weight and <80 Wt .-%, more preferably between> 35 wt .-% and <75% by weight. This is due, in particular, to the low specific gravity of the cellulosic fibers which can be added as solids in comparison with the specific gravity of the other stated solids. In particular, it may be provided according to the invention that in method step e) a resin composition is applied which comprises at least one organic or inorganic pigment selected from the group consisting of burgundy blue, brilliant yellow, cadmium yellow, cadmium red, chrome oxide green, cobalt blue, cobalt blue, cobalt violet, Irrazine Red, Iron Oxide Black, Manganese Violet, Phthalocyanine Blue, Terra di Siena, Titanium White, Ultramarine Blue, Ultramarine Red, Umbra, Kaolin, Zirconium Silicate Pigments, Monoazoeba and Monoazo Orange, Thioindigo, Beta Naphthol Pigments, Naphthol AS Pigments, Pyrazolone Pigments, N Acetoacetic anilide pigments, azo metal complex pigments, diaryl yellow pigments, quinacridone pigments, diketopyrrolopyrrole pigments (DPP), dioxazine pigments, perylene pigments, isoindolinone pigments, copper phthalocyanine pigments and mixtures thereof.

Furthermore, it may be provided in one embodiment of the method that in process step e) a resin composition is applied, which has a curing agent, wherein the curing agent in the resin composition, for example, in a concentration between> 0.05 wt .-% and <3.0 % By weight, preferably> 0.15% by weight and <2.0% by weight, more preferably between> 0.5% by weight and <2.0% by weight. The provision of a hardener in the resin composition makes it possible to optimize the setting or hardening behavior of the resin composition in dependence on the paper applied to the plate-shaped support and / or furthermore to provide a particularly rapid provision of the printing substrate, which may be advantageous in particular immediately followed by printing on the application of the printing substrate.

According to one embodiment of the method, the hardener may have, for example, a solution of organic salts. The hardener preferably has an acidic pH, preferably between> pH 0.5 and <pH 7, preferably> pH 0.5 and <pH 6. In a particularly preferred embodiment of the invention, a so-called latent hardener is used as a hardener. Deterent hardeners are characterized by the fact that, after their addition to the resin, on the one hand sufficient processing time at room temperature and, on the other hand, the shortest possible curing time at the subsequent processing temperatures becomes. The effect of the latent hardeners is that they are ineffective at ordinary temperatures and only release an acid at elevated heat or due to a chemical reaction, which accelerates the curing process. Examples of latent hardeners include alkyl or alkanolamine salts of sulfurous acid, sulfamic acid, 3-chloro-1,2-propanediol, p-toluenesulfonic acid, morpholine, ammonium sulfate,

Ammonium chloride, ammonium sulfite, ammonium nitrate, ethanolamine hydrochloride, dimethylethanolammonium sulfite, diethanolammonium sulfamate or maleic acid.

In particular, the hardener may be an aqueous, preferably non-ionic solution. An example of a suitable hardener is MH-180B (Melatec AG, Switzerland).

At least one, for example, all of the resin compositions applied in step e) may contain, in addition to the aforementioned ingredients, further ingredients such as rheology agents for adjusting viscosity, water, flow improvers, preservatives, surfactants, antifoaming agents or the like.

In the method according to the invention, both the application of a resin composition on the plate-shaped support according to process step b), as well as the application of a printing substrate on the plate-shaped support according to process step e), by application rollers, with a spray, doctoring, blade coating, air brushes, Cast iron facilities, slot nozzles, curtain or other suitable devices done. After application of the resin composition in process step e), a drying step may follow in which at least the surface of the resinous layer is at least partially dried. For this purpose it can be provided that a surface temperature on the surface to which the resin composition has been applied - In

between> 75 ° C and <125 ° C, preferably between> 80 ° C and <110 ° C, in particular between> 90 ° C and <100 ° C is generated. To produce a corresponding surface temperature, for example, IR emitters, NIR emitters, nozzle dryers or similar devices are suitable. The surface temperature mentioned is preferably set for a period between> 1 s and <600 s, preferably between> 5 s and <400 s, more preferably between> 10 s and <300 s.

Following the drying of the printing substrate, for example by heat, a subsequent treatment of the resin composition applied in process step e) and optionally dried, for example with UV radiation, can furthermore take place.

The thus treated plate or the carrier with the applied printing substrate can then be printed directly, in particular using flexographic printing, offset printing or screen printing, as well as in particular by means of digital printing techniques, such as inkjet or laser printing method. In particular, the latter offer a high possible variance of the order quantity, so that the method described here is particularly advantageous in digital printing techniques.

With regard to the printing and thus the formation of a decoration or a decorative layer on the support, it is provided in a method described here that according to method step f) the support is printed with an application amount of radiation-curable printing ink, such as radiation-curable ink. In particular, a printing ink, such as an ink which can be cured by UV radiation, thus being UV curable, is used for the printing. In this case, it may be provided, in particular, that the ink and / or ink has corresponding radiation- or photo-induced polymerizing constituents and optionally suitable photoinitiators. Examples of suitable constituents are acrylates, epoxides or cyclic amines, such as ethyleneimine. With regard to the use of radiation-curable printing ink for printing on the support, it is provided in the method described here that after printing on the support, curing of the previously applied printing ink according to process step g) by treating the printing ink with radiation, in particular with UV radiation , he follows.

Under UV radiation can be understood in particular a radiation that is in a wavelength range of for example 10-380nm, about 100-380nm. In this case, such radiation can be generated, for example, in a conventional manner by using medium-pressure lamps. By way of example, a gas discharge lamp, such as a mercury vapor lamp, or a UV LED can be used.

The use of a radiation-curable printing ink, for example a radiation-curable ink, has the advantage that the printing ink need not be subjected to a time-consuming drying step, but rather can be hardened comparatively quickly by the influence of, for example, UV radiation. Although the cured ink obtains its final hardness due to the curing mechanism and a corresponding complete curing, if necessary after a relatively longer period of time, already after the aforementioned very short time, a further treatment of the carrier already take place.

With regard to the aforementioned drying step or curing step according to method step g), it is further provided in the method described here according to method step h) that at least one parameter of radiation used in method step g) is adapted to the application quantity of radiation-curable printing ink. It has surprisingly been found that, in particular, a previously described method may allow, with a short processing time, sufficient and particularly gentle hardening of the radiation-curing printing ink. In detail, by adjusting the radiation or at least one parameter of the radiation to the application rate of the radiation-curing ink, it can be achieved that the radiation is applied with one or more parameters that can sufficiently enable curing of the ink and further high line speeds can be achieved. On the other hand, it can be made possible that the heat load of the carrier plate can be kept particularly low by the least possible effect of the radiation. This allows a very gentle treatment of the support plate are made possible in a curing of the ink.

Furthermore, in contrast to otherwise conventional structures, according to which the radiation is set with uniform parameters, a particularly simple adaptability to the desired field of application or to the desired decor can be made possible. In this case, however, can be dispensed with costly conversion measures, since the curing is adjusted by a simple adjustment of one or more parameters of the radiation used, which is optionally particularly easy to implement. As a result, production losses due to adaptation work can be reduced or completely avoided, thus increasing productivity.

In addition, can be made possible by an adjustment of the radiation and thus by limiting the radiation to parameters that are selected depending on the order amount, a significant energy gain. This can make the process particularly economical. Furthermore, depending on the parameter setting of the printed carrier different properties, such as chemical resistance, adhesion, scratch resistance, gloss, and wear sensitivity, have. Thus, by adapting the radiation parameters, the printed carrier can be adapted in terms of its properties to the desired field of application, such as the subsequent treatment steps or potentially subsequently applied layers.

With respect to the parameters to be set, these can preferably be calibrated prior to a printing or curing process being performed, so that, for example by a control unit, when changing the application quantity of the ink in a predetermined pattern, the or the corresponding parameters can be adapted particularly reliably. For example, the calibration can be based on or performed using different printing inks, or different travel speeds of the carrier, so that the distance between the printing unit and the radiation unit and the corresponding travel time of the carrier between the print head and the radiation unit can be included as well as the influence different curing behavior of different inks or different order quantities of printing inks. It is provided that method step h) is based on a determined by at least one sensor during the printing process order quantity of the radiation-curable ink. In this embodiment, the application quantity actually used, for example using corresponding sensors, can be detected and used accordingly. Thus, an adjustment of the cure may not or not exclusively be based on preset values but rather reflects the actual conditions of the printing process. As a result, hardening can always be carried out using the correct parameters even if the actual application quantity differs from the previously set values. In particular, it may be provided that the application quantity is determined using at least one sensor. In this embodiment, a determination of the order quantity can thus be determined in situ and forwarded to a control unit or to a radiation unit, which can simplify a highly accurate irradiation. In particular, on the basis of the distance of the radiation unit from the print head in combination with the travel speed based on the specifically determined data of the application quantity, the radiation unit, for example by the control unit, can be activated.

In principle, it may be freely selectable whether only one sensor is used or a plurality of sensors. Furthermore, the choice of the sensor, that is to say in particular the mode of operation of the sensor (s), is not fundamentally limited in the sense of the present invention. Insofar as a plurality of two or more sensors is used, the same or different sensors can be used.

In particular, when determining the specific application quantity, it may be advantageous to calibrate the corresponding sensor by determining the effect of different amounts of ink and possibly different types of inks or colors on the sensor, as already described above.

Accordingly, it is provided that at least one parameter of radiation used in method step g) is adapted during the printing of the carrier according to method step f). In this embodiment, an adaptation is thus not, as is basically possible, prior to printing an entire decoration, but at least partially before individual decor areas. For example, an adaptation of the at least one parameter can take place simultaneously with a printing process. The radiation thus does not need to be adapted to an averaged value or a minimum value or a maximum value of the application thickness, but rather an adaptation during a decor pressure can be realized during the printing of the decoration on individual and possibly different regions of the decoration. This allows a particularly accurate adjustment to the entire decor image and therefore a particularly effective adaptation.

With regard to the sensor, it may be provided that the determination of the application quantity of the radiation-curable ink is carried out during the printing process using at least one optical sensor which scans or detects a discharge region of a print head. For example, the transmission of radiation can be determined, which is passed through the ink jet so as to obtain conclusions about the amount of ink and thus the order quantity. This embodiment can allow a particularly accurate determination of the order quantity. It may be advantageous if each printhead is associated with a sensor or that each of the printheads is provided with a sensor.

Alternatively or additionally, it may be provided that the determination of the application quantity of the radiation-curable ink is carried out during the printing process using at least one optical sensor which detects the printed substrate. If necessary, this embodiment can be implemented in a particularly simple and cost-effective manner. Because in this embodiment, conventional printheads can be used without these need a significant conversion. In particular, in this embodiment, it may be advantageous if the determination of the order amount takes place taking into account the applied color, ie when the type of color applied flows into the calculation. For this purpose, it can be determined, for example based on the control data, which color should be discharged at which position. Alternatively or additionally, it may be provided that the determination of the application amount of the radiation-curable ink is carried out during the printing process using a flow sensor which detects a color line upstream of a print head or within a print head. In this case, the flow sensor, which is preferably provided on or in front of all the corresponding print heads, determine the concretely flowing amount of ink very precisely, which flows to the print head or through the print head. In this case, the position of the flow sensor can be advantageously selected depending on the system used.

It can also be provided that a warning is issued in the case of a deviation of the determined order quantity from the desired order quantity. In this embodiment, it can thus be prevented that, if necessary, an excessive rejection must take place in the event of a malfunction of the print head. Because based on the warnings, if necessary, a printing operation can be interrupted or readjusted, so as to allow printing of the carrier in the desired manner. In this case, a warning can be issued, for example, if the deviation of the determined order quantity from the desired order amount is outside predetermined limits, so as to enable a desired tolerance. The warnings can be done in various ways, such as a warning tone or an optical indication. To protect the applied decorative layer may also be applied a wear or cover layer above the decorative layer in a subsequent process step, which protects the decorative layer in particular from wear or damage by dirt, moisture or mechanical effects such as abrasion. With respect to the wear or cover layer, it may be provided that the wear layer hard materials such as titanium nitride, titanium carbide, silicon nitride, silicon carbide, boron carbide, tungsten carbide, tantalum carbide, alumina (corundum), zirconium oxide or mixtures thereof, to the wear resistance of the layer increase. It may be provided that the hard material is present in an amount of between 5% by weight and 40% by weight, preferably between 15% by weight and 25% by weight, in the wear layer composition. The hard material preferably has a mean particle diameter D50 between 10 μm and 250 μm, more preferably between μm and μm. In this way, it is advantageously achieved that the wear layer composition forms a stable dispersion and segregation or settling of the hard material in the wear layer composition can be avoided. To form a corresponding wear layer, it is provided in one embodiment of the invention that the hard-material-containing and radiation curable composition in a concentration between 10 g / m ² and 300 g / m ^2, preferably between 50 g / m ² and 250g / m ² is applied. In this case, the application can be applied for example by means of rollers, such as rubber rollers or by means of pouring devices. In a further embodiment of the invention, it may be provided that the hard material is not present in the composition at the time of application of the wear layer composition, but is scattered as particles onto the applied wear layer composition and this is subsequently cured.

For this purpose, it can preferably be provided that a curable composition is applied as cover and / or wear layer and a curing process takes place before the introduction of the structure only to the extent that only partial hardening of the cover and / or wear layer takes place. In the thus partially cured layer, a desired surface structure is impressed by means of suitable tools, such as a hard metal structure roller or a punch or a press, such as a short-cycle press. The embossing is preferably carried out in accordance with the applied decor. In order to ensure sufficient conformity of the structure to be introduced with the decor, provision can be made for the carrier plate and the embossing tool to be aligned with one another by corresponding relative movements, for example based on corresponding, for example, optical markings. in the Following the introduction of the desired structure in the partially cured cover and / or wear layer is a further hardening, such as a final curing, the now structured covering and / or wear layer. In addition, it can be provided that the wear and / or cover layer is applied as a resin layer, such as melamine resin layer, or as a radiation-curable or at least partially radiation-curable composition, for example based on an acrylate lacquer, an epoxy lacquer, or a urethane acrylate. Furthermore, the cover and / or wear layer may comprise means for reducing the static (electrostatic) charge of the final laminate. For example, it may be provided that the cover and / or wear layer has compounds such as choline chloride. The antistatic agent may, for example, in a concentration between> 0.1 wt .-% and <40.0 wt .-%, preferably between> 1.0 wt .-% and <30.0 wt .- in the cover and / or composition for training wear layer be included.

It can also be provided that the structuring is generated in the course of the printing process. For this purpose, it can be provided, for example, that a multiple application of paint takes place, for example, with respective at least partial or complete curing in such a way that raised areas arise over the printing substrate, which result in a desired three-dimensional structure. A wear and / or cover layer can then be applied to the structure produced in this way. On the side opposite the decorative side, a counter-pull can be applied. It is particularly preferred that the counter-pull is applied in a common calendering with the paper or non-woven on the decorative side or independently. In a further embodiment of the invention, it may be provided that a return only after the application of the decorative image is applied to the opposite side of the decorative layer of the plate-shaped carrier. It can be provided in particular that the counter-pull is applied in a joint step with the application of an overlay as a cover and / or wear layer.

In particular, however, it may be preferred within the scope of the invention if it is dispensed with the application of a counter-pull.

Furthermore, the plate-shaped carrier can have a profiling, at least in one edge region. It may be provided in particular that the decor is also applied in the profiling, so that the profiling takes place before applying the decorative layer on the plate-shaped carrier. Alternatively or additionally, a profiling can also take place after the decorative layer has been applied. In a profiling according to the invention, it is provided that a decorative and / or functional profile is introduced by means of suitable material-removing tools at least in a part of the edges of the decorative panel. In this case, a functional profile is understood, for example, to mean the introduction of a tongue and / or groove profile into an edge in order to make decorative panels connectable to each other via the introduced profilings. A decorative profile in the sense of the invention is, for example, a chamfer introduced in the edge region of the decorative panel in order to simulate, for example, a joint between two interconnected panels, as occurs, for example, in so-called plank flooring.

In a partial profiling of the decorative panel not all to be provided in the final panel profiles are introduced, but only a part of the profiles to be provided, while other profiles are introduced in a subsequent step. Thus, for example, it may be provided that the decorative profile to be provided in a panel, such as a chamfer, is introduced in a working step, while the functional profile, such as tongue / groove is introduced in a subsequent step.

By applying the decoration only after the at least partial profiling of the carrier, for example by the above-described methods such as direct printing method, a removal or damage of the decoration in the course of profiling is advantageously avoided. As a result, the decor also corresponds to the desired imitation of a natural material, for example, in the areas of the profiling in a detailed manner.

In summary, the above-described method can enable high adaptability with simultaneously high throughput and gentle processing.

It can be provided that method step h) is based on a predetermined application rate of the radiation-curable ink. In this embodiment, at least one parameter of the radiation used can be adjusted based on an order quantity which is passed on, for example, from a control unit to the printing unit or to one or more print heads. Thus, for example, a control signal for the print heads can be transmitted correspondingly to a radiation device which sets the parameters for a radiation-based curing of the ink based on the order quantity thus transmitted. In this embodiment, the method can be realized particularly inexpensively, since it is possible to dispense with any sensors or the like which detect the application quantity. In addition, for example, a print image to be printed or the amount of printing associated therewith may be taken into consideration in advance, which may thus also include any setting delays of the parameters. Furthermore, provision can be made for at least one parameter of radiation used in method step g) to be adapted independently of one another and, for example, differently in a plurality of regions which are locally different from one another. In this embodiment, it can be made possible in a particularly advantageous manner that even if different application rates of radiation-curing printing ink are applied in different areas of the carrier plate, at least one radiation parameter can be adapted particularly effectively. In this case, the locally different regions can be provided or arranged parallel to a direction of travel of the carrier plate and / or the locally different regions can be arranged in a direction perpendicular to the direction of travel of the carrier plate. With reference to the direction of travel, this is in particular the direction in which the carrier plate is transported by a printing unit. Again, this configuration can in turn allow a particularly accurate adjustment to the entire decor image and therefore a particularly effective adaptation.

Furthermore, it can be provided that the at least one adapted parameter of the applied radiation comprises the number of radiators. In this embodiment, the adaptation of the at least one radiation parameter can be carried out in a particularly simple manner, since it is easy to handle this parameter by means of a corresponding control and, furthermore, commercial emitters can be used. As a result, a realization is particularly easy. In this case, the number of radiators, that is, the active during the curing or working radiators, be adjusted in a direction that is parallel to the direction of travel of the support plate and / or in a direction perpendicular thereto.

Alternatively or additionally, it can be provided that the at least one adapted parameter of the applied radiation comprises the power of at least one radiator. In this embodiment, the power of one or more radiators can thus be varied, whereby a particularly accurate and defined adjustment can be possible. As a result, in this embodiment, even with comparatively small differences in the order quantity, a high degree of adaptation always takes place. Alternatively or additionally, it can be provided that the at least one adapted parameter of the applied radiation comprises the irradiation duration of the radiation-curable ink. This parameter can be adjustable, for example, by a variation of the line speed of the carrier plate, that is to say the speed with which the printed carrier plate passes through an irradiation unit. Also, this parameter can effectively enable exposure of the radiation to the ink and thus adjusting the curing conditions.

In principle, it can be provided in the method described here that method step g) is realized by using a power of the radiation, which occurs in particular on the surface of the irradiated substrate, in a range from> 100W / cm to <200W / cm, preferably from > 110W / cm to <170W / cm, for example, from> 120W / cm to <160W / cm, about 145 W / cm are.

For example, a radiation source or a plurality of radiation sources can be used which can be arranged one behind the other and / or next to each other in the transport direction of the carrier. In an exemplary wavelength range of 230-410 nm and the use of three sequentially connected radiators, for example with a power of 145 W / cm, the total dose of irradiation incident on the ink can be adjusted, for example, to a range of> 400 mJ / cm ² to <1200 mJ / cm ² , in particular> 600 mJ / cm ² to <1000 mJ / cm ² , for example from> 700 mJ / cm ² to <900 mJ / cm ² , for example 830 mJ / cm ² . Thus, the dose applied to the ink may be a suitable parameter to be adjusted according to the invention. By way of example, using three UV emitters in series, for example a spot-on time in the direct focus of the emitter, which may have a range corresponding to the direction of travel of the emitter of approximately 10 mm, may be approximately 0.024 s by way of example, with an increased residence time Focus, which may have a range corresponding to the direction of movement of the carrier of about 50 mm, of about 0.12 s amount.

In principle, total irradiation durations, which may comprise both the direct focus and the extended focus, may be present in a range of> 0.05 s to <20 s, preferably> 0.1 s to <2 s, for example> 0.2 s to <0 , 5 s lie. To achieve the above values, for example, a speed of the carrier may be set in a range of, for example, 25 m / min.

With regard to further advantages and technical features of the method described above, reference is expressly made to the following description of the device, to the figures, and the description of the figures, and vice versa.

The subject of the present invention is further an apparatus for producing a printed panel comprising

- A feeding device for feeding a plate-shaped carrier;

optionally an application unit for applying a resin layer to the supplied carrier;

optionally a feeding device for applying a paper or non-woven layer to the plate-shaped carrier;

optionally a unit for calendering a layer structure comprising the support, the resin layer and the paper or nonwoven layer;

optionally an application unit for applying a printing substrate to the support; a printing unit for printing the substrate with radiation-curable ink; and

a radiation unit for treating the printed substrate with radiation for curing the radiation-curable ink, wherein it is provided - a control unit which is fed with data of at least one sensor relating to a determined during the printing process Auftagsmenge the radiation-curable ink, the control unit based on the order amount at least determines a parameter of radiation emitted by the irradiation unit, and which is connected to the irradiation unit for communicating the at least one parameter through a data connection, and wherein

the irradiation by the irradiation unit can be carried out on the basis of the at least one parameter. By a vorbeschriebe device, it can be achieved that a panel is printed with a straghlungshärtbaren ink and the ink is radiation-cured, in particular, the curing process can be particularly effective and gentle.

With regard to the specific features and advantages of such a device, reference is made to the method described in detail above.

With regard to further advantages and technical features of the device described above, reference is expressly made to the description of the method to the figures, and the description of the figures, and vice versa.

The invention is explained below with reference to the figures and an embodiment. Fig. 1 shows a device in an embodiment of the invention in a first mode of operation;

Fig. 2 shows the device of Figure 1 in a second mode of operation and

FIG. 3 shows the device from FIG. 1 in a second operating mode.

1 shows an apparatus for producing a printed panel in an embodiment of the present invention for carrying out a method according to the present invention. The device comprises a feed device 10 for feeding a plate-shaped carrier 12, so that the carrier 12 runs in the direction of the arrow 14 as a travel direction. Downstream of the feed device 12 is an application unit 16 for applying a resin layer 18 to the supplied carrier 12. In the direction of travel behind the application unit 16, a feed device 20 for applying a paper or nonwoven layer 22 to the plate-shaped carrier 12 is arranged. Not shown is an adjoining unit for calendering, in particular under heat of a layer structure comprising the carrier, the resin layer 18 and the paper or nonwoven layer 22.

In order to prepare a printing of the carrier 12, according to FIG. 1, an application unit 24 is also provided for applying a printing substrate 26 to the carrier 12. In the direction of travel of the carrier 12 behind the application unit 24, printing of the carrier 12 can follow. For this purpose, a printing unit 28 is provided for printing the carrier 12 with an application amount of radiation-curable ink 30. To cure the radiation-curable ink 30, a radiation unit 32 for treating the printed substrate 12 with radiation to cure the radiation-curable ink 30 is provided so that the substrate 12 is provided with cured ink 44. With reference to the radiation unit 32, it is shown in FIG. 1 that the radiation unit 32 has five radiators 34, 36, 38, 40, 42. These can be arranged side by side, but can basically any arrangement of the emitters 34, 36, 38, 40, 42 of the present invention be included.

FIG. 1 further shows that the device has a control unit 46, which is connected to the printing unit 28 and the radiation unit 32 for data transmission with a data connection 48, for example. As a result, the control unit 46 can be fed with data concerning an application quantity of the radiation-curable ink 30 and can determine at least one parameter of radiation emitted by the radiation unit 32 on the basis of the application quantity. The data relating to the application quantity may correspond to the data transmitted to the printing unit 28 or may be producible by sensors, not shown, for determining the applied printing ink 30.

For example, the determination of the application amount of the radiation-curable ink during the printing operation may be performed using at least one optical sensor that detects a discharge area of a print head. Alternatively or additionally, it may be provided that the determination of the application quantity of the radiation-curable ink is carried out during the printing process using at least one optical sensor which detects the printed substrate. It may alternatively or additionally be provided that the determination of the application amount of the radiation-curable ink is carried out during the printing process using a flow sensor which detects a color line upstream of a print head or within a print head.

This makes it possible for the control unit 46 to transmit the at least one parameter to the radiation unit 32. The radiation unit 32 in turn can print the ink 30th cure using this parameter. This is likewise shown in FIGS. 2 and 3, the above description likewise being valid for FIGS. 2 and 3.

FIG. 1 shows that a comparatively large application quantity of radiation-curable ink 30 has been applied to the carrier 12. To cure the ink 30, therefore, all five radiators 34, 36, 38, 40, 42 are used.

FIG. 2 indicates that a comparatively small application quantity of radiation-curable ink 30 has been applied to the carrier 12. Therefore, only three emitters 34, 38, 42 are used to cure the ink 30.

FIG. 3 shows a further example. According to FIG. 3, part of the printing ink 30 with a comparatively small application amount of radiation-curable printing ink 30 is applied to the support 12, and a part of the printing ink 30 is also applied to the support 12 with a comparatively high application quantity of radiation-curable printing ink 30. In this case, hardening or irradiation of the printing ink 30 can take place locally differently by using the radiators 34, 36, 38 and 42. It can be seen that a diverse adaptation can also be possible with differently printed decor areas.

Regardless of the specific embodiment of the device or the method, the use of five radiators 34, 36, 38, 40, 42, for example, the following parameter selection done, with the order quantities refer to the entire decor. For an application quantity of < ² g / m ² , for example, a spotlight can be used; for an application quantity of> ² g / m ² to <5 g / m ² , for example, two emitters can be used, with an application rate of> 5 g / m ² to <8 g For example, three radiators can be used / m ² , with an application rate of> 8 g / m ² to <10 g / m ² , for example, four radiators can be used and for an order quantity of> 10 g / m ² , for example, five radiators can be used, the above values being purely exemplary.

Specifically, it is in principle possible, for example, for a given UV-curable ink to be used with amounts of ink applied of <1 ml / m ² with a UV emitter, the ink having a dose of 280 mJ / cm ² . Furthermore, it can be provided that with applied quantities of ink of> lml / m ² to <5 ml / m ² with two consecutively arranged UV lamps is used, wherein the ink acts a dose of 550mJ / cm ² , and that with applied amounts of ink of> 5 ml / m ^{2 is worked} with three successively arranged UV lamps, wherein the ink has a dose of 830mJ / cm ² acts. The feed rate of the panel is 25 m / min in all examples. In this case, when using three series-connected UV lamps, for example, a residence time in the direct focus of the radiator, which may have a range corresponding to the direction of movement of the carrier of about 10 mm, be of example about 0.024 s, the residence time in an extended Focus, which may have a range corresponding to the direction of movement of the carrier of about 50 mm, of about 0.12 s amount. Further, the dose was measured in the wavelength range 230 - 410 nm using a mercury radiator. In a manner obvious to the person skilled in the art, the abovementioned parameters may differ, for example, in addition to the specific ink used, based on a doping of the radiator.

The dose can be determined, for example, by a product marketed under the name "UV Micro-Puck" by UV-Technik Meyer GmbH.

The above-mentioned adjustments are also dependent on the desired curing result, which is realized by the influence of the radiator on the ink. Consequently For example, the radiation used to act on the ink may be selected in particular against the background that the ink is optionally compressed together with a layer disposed on the ink, such as melamine resin layer or lacquer layer, for introducing haptic perceptible structures. For this purpose, if necessary, a stronger curing or a stronger dose acting on the ink may be necessary than with an ink layer which is not subjected to compression.

Reference numerals:

10 feeder

12 carriers

14 arrow

16 application unit

18 resin layer

20 feeder

22 paper or nonwoven layer

24 application unit

26 printing substrate

28 printing unit

30 radiation-curable ink

32 radiation unit

34 spotlights

36 spotlights

38 spotlights

40 spotlights

42 spotlights

44 hardened printing ink Control unit data connection

Claims

claims

A method of manufacturing a printed panel comprising

Process steps:

a) providing a plate-shaped carrier (12);

b) optionally applying a resin layer (18) on the plate-shaped carrier

(12);

c) optionally applying a paper or nonwoven layer (22) on the

plate-shaped carrier (12);

d) optionally calendering the resulting layer structure, in particular at a temperature between> 40 ° and <250 ° C, and

e) optionally applying a printing substrate (26) on the plate-shaped support (12);

characterized in that

the method comprises the further method steps:

f) printing the carrier (12) with an application amount of radiation-curable

Printing ink (30) and;

g) curing the previously applied printing ink (30) by treating the

Printing ink (30) with radiation, wherein

h) at least one parameter of radiation used in method step g) is adapted to application quantity of radiation-curable printing ink (30), wherein

Method step h) is based on an application quantity of the radiation-curable ink (30) determined by a sensor during the printing process, wherein at least one parameter of radiation used in method step g) is adapted during printing of the carrier (12) according to method step f).

2. The method according to claim 1, characterized in that determining the

Application rate of the radiation-curable ink (30) during the Printing is performed using at least one optical sensor that detects a discharge area of a print head.

3. The method according to claim 1 or 2, characterized in that the determination of the application amount of the radiation-curable ink (30) is carried out during the printing operation using at least one optical sensor which detects the printed carrier (12).

4. The method according to any one of claims 1 to 3, characterized in that the

Determining the application amount of the radiation-curable ink (30) during the printing operation is performed using a flow sensor that detects a color line upstream of a printhead or within a printhead.

5. The method according to any one of claims 1 to 4, characterized in that when a deviation of the determined order quantity of the desired order quantity, a warning is issued.

6. The method according to any one of claims 1 to 5, characterized in that

Method step h) is based on a predetermined order quantity of

radiation-curable ink (30).

7. The method according to any one of claims 1 to 6, characterized in that

at least one parameter of radiation used in method step g) is adapted independently of one another in a plurality of locally different regions.

8. The method according to any one of claims 1 to 7, characterized in that the at least one adapted parameter of radiation used in step g) comprises the number of radiators (34, 36, 38, 40, 42).

9. The method according to any one of claims 1 to 8, characterized in that the

at least one adapted parameter of radiation used in step g) comprises the power of at least one radiator (34, 36, 38, 40, 42).

10. The method according to any one of claims 1 to 9, characterized in that the

at least one adapted parameter of radiation used in step g) comprises the irradiation duration of the radiation-curable ink (30).

11. The method according to any one of claims 1 to 10, characterized in that

Method step f) is realized using a digital printing method.

12. An apparatus for producing a printed panel, comprising

a feeder (10) for feeding a plate-shaped carrier (12); optionally an application unit (16) for applying a resin layer (18) to the supplied carrier (12);

optionally a feeding device (20) for applying a paper or non-woven layer (22) to the plate-shaped carrier (12);

optionally a unit for calendering a layer structure comprising the support (12), the resin layer (18) and the paper or non-woven layer (22); optionally an application unit (24) for applying a printing substrate (26) to the carrier (12);

a printing unit (28) for printing the substrate (12) with radiation-curable ink (30); and a radiation unit (32) for treating the printed substrate (12) with radiation to cure the radiation-curable ink (30), wherein it is further provided

a control unit (46) which can be fed with data of at least one sensor relating to an applied quantity of the radiation-curable ink (30) determined during the printing operation, wherein the control unit determines at least one parameter of radiation emitted by the irradiation unit (32) on the basis of the application quantity, and which is connected to the irradiation unit (32) for communicating the at least one parameter through a data link (48), and wherein the irradiation by the irradiation unit (32) is executable based on the at least one parameter.